Many manned and unmanned (“UAVs”) aircraft driven by propeller are susceptible to ground threats such as small arms fire and manned-portable air defense systems (“MANPADS”). Given the nature of typical missions and operations, it may be desirable to reduce audible detectability. The ability to cancel or substantially reduce critical tones of a propeller system's acoustic signature may be important in reducing these vehicles' acoustic signatures and enhancing mission effectiveness. Small UAVs typically use fixed pitch propellers which are neither subject to the complexities nor the stresses of variable pitch propellers which are used for manned vehicles or large UAVs. Hence, innovative propeller concepts which are subject to structural constraints may be better implemented on these less-complex systems, compared to manned vehicles or large UAVs.